I agree with this. Leave the switch in the HI position.
I think the LO position lowers the plate voltage. A few times my HI/LO
switch has been inadvertently toggled to the LO position. The symptom is
that you can't drive the amp to full power. I think the grid current runs
high as well, but I can't remember.
Many manual-tune amps have a CW/SSB switch which, as I recall, lowers the
plate voltage. You can tune up in either mode, but won't get full power
unless you use the SSB position. I think you can tune the 87A in LO mode as
well. It may be that the damage occurs when the stored tuning parameters are
for HI mode and are recalled when the switch is in the LO position. I would
think AlphaMax could compensate for that, and/or the protection circuits
would just trip. However, I wouldn't bank on it. Safer to always make sure
the switch is in the HI position.
73, Dick WC1M
> -----Original Message-----
> From: Paul Young [mailto:paul@g0hwc.com]
> Sent: Sunday, May 04, 2008 11:37 AM
> To: Jerry Stern; Amps@contesting.com
> Subject: Re: [Amps] Alpha 87A Voltage Switch
>
> Hi Jerry,
> I have been told that is not safe to use the amp with the
> switch
> in "LO"
> Was put on "something to do with FCC rules" I think. But will cause
> damage if used..
>
> Im sure you will get full details from others
>
> Paul G0HWC
> http://www.g0hwc.com See my Station details :-)
> Echolink G0HWC-L 381900 "2m link"
>
>
> ----- Original Message -----
> From: "Jerry Stern" <jsternmd@earthlink.net>
> To: <Amps@contesting.com>
> Sent: Sunday, May 04, 2008 3:58 PM
> Subject: [Amps] Alpha 87A Voltage Switch
>
>
> > What is the intended purpose of the "Lo" voltage position on the
> Alpha 87A
> > front panel??
> >
> > 73 Jerry
> > K1JOS
> >
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> >
> >
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>
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